We are interested in how bacteria and bacterial products shape the development of subsequent innate and adaptive immune responses with the goal of understanding how these host-microbe interactions influence pathogenesis of infections, autoimmunity, allergy, and cancer. In 2013, we have focused on host defense against the bacterial pathogen Staphylococcus aureus. These studies have uncovered the role of the IL-20 receptor in promoting S. aureus skin infection, providing insight into the regulation of key anti-staphylococcal inflammatory pathways such as IL-1 and IL-17 during infection. In addition, in 2013 we have identified the role of dietary exposures and host responses to intestinal commensals on development of IL-17-related immune responses that are relevant to susceptibility to infection and inflammatory diseases. With these studies we have enhanced our understanding of the mechanisms controlling skin and mucosal host defense and identified potential pathways that can be targeted to enhance efficacy of vaccines and therapies against cancer, infection, and immune-mediated diseases.